Limit switch



w. D. SMITH LIMIT SWITCH Sept. 6, 1927.

Filed 00:. 25. 1926 INVENTURF v n. I.

AT T DRNEYS Patented Sept. 6, 1927.

UNITED stares WILLlAlYI n. s ITI-I, or new ORLEANS, LoUIs-IAn-A, assrenon TO THE GOVERNMENT em wette T E he was LIMIT SWITCH.

app icant fi ed peteher i 4 92.6.- jse ia NQ- me e.

(QRANTEP UNDEB IHE A tor newt 1 st; s ea 62 Y r Th app i is ma under the act o and the invention herein described and claimed may be used by the Government 5 of the United States or any of its officers or empl yee n t e pres cu't o f work f r t efi'e rnment, or any person in the Un d ate With u payment o me e any rayalty thereon. U

10 The object of my invention is to provide a device which adapted accurately to serve as a check circuit on any machine or de vice driven by electricity.

The nature, characteristic features, and scope of my invention will be more readily understood from the following description taken in connection with accompanying drawings, forming a part hereof, wherein:

Figure l is a top view of my device showing the positions of the parts when the circuit is closed; Figure 2 is a top view of my device showing the positions of the parts when the circuit is open; Figure 3 is a side view of my device; Figure 4 is a front View of my device showing the binding posts which serve as connections for the device.

Referring to the drawings, A represents the base of a box made of fiber, or other suitable material, which encloses the device. A represents one side of this box, onwhich is mounted the knife switch I. B represents an arm made of fiber,,or other suitable material, fastened to the base A by means of a bolt B. C represents an extension made of brass, or other suitable material, to the arm B. C represents the point of the extension C. D'represents a. trigger made of brass, or other suitable material, mounted in a notch in the arm B under the extension C. D represents the notch inthe trigger D. represents a fine spring attached to the trigger D and to the upper end of the arm B, in the position shown in Figure 1 and Figure 2. F represents a cord attached to the trigger D and passing through the screw-eye F and out of the box through a hole in the side. F represents a. small screw-eye through which the cord F passes. G represents a bumper made'of fiber, or other suitable material, attached to the base A by a bolt G. H represents a spring attached to the base A and to the arm B by ,sctewhoolts H. H represents the screwhoks by means ofwhich-the spring H is attached to the base A and to the arm B,

l r p es n sa kni itch a ched to. he eide'A by't o s 1C I pr sen h belt whith' hold the knif wit I and the b nding pos s .J P ac 1& rep ent thejhandl of e ad f th swi c I- rep esen a platemade f br s, other suitable ma erial? attache to. t handl K the posi ion shown- KL epresent a spring attached to the handle K and to the side of the box A. L represents the screw which holds the end of the spring L to the side A. M represents a slot in the side of the box, through which slot the extension C project-s. N represents a hole in the base A through which hole a bolt may be passed v to hold the device in any position desired. 0 represents the top, or lid, of the box enclosing the device, which top, or lid, is held closed by the catch 0.

The structural parts constituting my device may be constructed of any material which is sufficiently strong and durable to withstand the strain of the operations to which it may be subjected in breaking the electric circuit, provided that the material used for the box, for the arm B, for the bumper G, for the base of the switch I, and for the handle K must be a non-conductor of electricity. I prefer to construct the box which encloses the device of fiber. I refer to construct the arm B, the bumper the base of the knife'switch I, and the handle K of fiber. I prefer to construct the extension C, the trigger D, and the plate D of brass.

. For operating the device a cord F is attached to the end of the trigger D, is passed through a small screw-eye F and through a hole in the side of the box. Electric connections are fastened to the binding posts J. When assembled the device is fastened in place by a flat-head bolt passing through the hole N in the base A.

In practicing my invention, I place the device on a machine so that some projection from a gear, sprocket, or other part, on the machine will engage the extension C of the arm B. The parts of the device are then put in the positions shown in Figure 2 and the electric current is turned on. To put the switch I into contact with the two connections, as shown in Figure 1. At the required time for the machine to cease operating a projection engages the extension G of the arm B and pulls the arm B over until the notch D in the trigger D engages the plate K. When the point C of the extension 0 slips off of the projection the arm B is pulled back quickly against the bumper G by the spring H, and the blade of the switch I is pulled out of'contact, as shown in Figure 2,

- breaking the electric circuit and stopping the machine.

From the foregoing it is thought that the construction, operation, and many advan tages of the herein described invention will be apparent to those skilled in the art, Without further description, and it will be understood that various changes in size, shape, proportion, andminor details of construction may be resorted to without departing from the spirit or sacrificing any of the advantages of the invention. V

I claim:

A limit switch comprising a support, an arm pivoted thereon, a spring having one end attached to the support and its otherend attached to said arm to hold the latter in a given position, a trigger pivoted on said arm, a pivoted switch element, a plate projecting therefrom and adapted tobe engaged by said trigger to normally hold said switch element inactive, means for operating said trigger to release the switch element, a spring attached to the support and said element for moving the latter to its active position when released, a spring attached to said arm and trigger for holding the latter ina positionto reengage said plate when said arm is moved in the direction of said switch element, and a bumper mounted on the support for limiting movement of said arm in one direction.

WVILLIAM D. SMITH. 

